CSN is a Crosby, Stills & Nash album released in 1977, the fifth album by the group, and the first without Neil Young since his entry into the band. It peaked at #2 on the Billboard Top Pop Albums chart; two singles taken from the album, Nash's "Just A Song Before I Go" and Stills' "Fair Game" peaked at #7 and #43 respectively on the Billboard Hot 100. 
In the interim since their last studio album of original material (1970's Déjà Vu), Crosby and Nash had recorded three albums as a duo. Stills pursued other projects, including a short career with Manassas and an album and tour with Young. 
CSN featured strong writing from all three members, the last time for seventeen years that the band would compose songs and handle vocals without major assistance from outside sources. The production of the album fit in well with the ruling aesthetic of the time as featured in other blockbusters such as the Eagles' Hotel California, Fleetwood Mac's Rumours: well-crafted, melodic songs played with precision and balance, essaying the personal travails of the authors. 
Many of Stills' songs on the album echo his marital problems, with "Dark Star" returning to the Latin rhythms he had favored all the way back to his Buffalo Springfield days. Crosby continued the existential probings consistent with much of his past work, and Nash offered a very stringent critique of Christianity with "Cathedral". Many tracks were sweetened with a string section, a first on a CSNY project. 
Joel Bernstein photographed the trio in serious poses aboard a boat, and initial copies of CSN bore that picture on the cover. The next picture Bernstein took of Crosby, Stills and Nash was a shot of them breaking into laughter at the thought of just having posed as "serious artists." The trio later decided that they liked the second photo better, and it was decided that all future pressings of CSN should bear the "laughter" photo. 
The album was released for compact disc on October 25, 1990, and then remastered at Ocean View Digital from the original tapes and reissued on September 20, 1994.